Description:SYSTEM FOR CONTINUOS IN-SITU MONITORING OF DISTRIBUTED TEMPERATURE OF MOLTEN MEDIUMS IN CORROSIVE ENVIRONMENTS

TECHNICAL FIELD
[0001] The present invention relates to temperature measurements, and more particularly relates to a system for continuous in-situ monitoring distributed temperature of molten metal, ore and Salts in a vessel, particularly in Hazardous Environments.
BACKGROUND
[0002] Accurate temperature measurement of molten metals, ores, and salts plays a critical role in industrial processes such as metal extraction, casting, and chemical processing. The temperature of molten materials must be precisely controlled to ensure process efficiency, quality, and safety. However, existing methods for temperature measurement in high-temperature environments present significant challenges that impact accuracy, reliability, and safety.
[0003] Infrared pyrometers and optical pyrometers are widely used for non-contact temperature measurement. However, these devices are highly sensitive to external interferences such as slag, smoke, or surface impurities, leading to inaccurate readings. Additionally, immersion-type thermocouples, which provide more direct temperature readings, have a short lifespan when exposed to extreme heat and harsh environments, making continuous measurement infeasible with current technologies.
[0004] A major issue in temperature monitoring is the non-uniformity of temperature distribution and rapid fluctuations in the temperature due to undesirable operation phenomena within large crucibles or vessels. Inconsistent temperatures across different depths significantly impact process efficiency and material properties, particularly in large-scale operations. Thus, the ability to measure and monitor temperature continuously at multiple depths is crucial for improving process control.
[0005] Another critical concern is the hazardous nature of high-temperature industrial environments. Manual contact-based temperature measurement methods pose significant risks to operators, including burns and exposure to toxic fumes. Furthermore, conventional continuous temperature measurement methods exhibit high error rates, making them unreliable for real-time process monitoring and control.
[0006] Therefore, there is a need for an advanced system that enables distributed, real-time continuous temperature measurement of molten metals, ores, and salts in hazardous industrial environments. The present system overcomes the limitations of conventional methods by providing accurate, multi-depth temperature readings while ensuring safety and operational efficiency. The present invention offers a novel approach to temperature monitoring, improving industrial automation, process control, and decision-making in extreme conditions.

SUMMARY
[0007] In one aspect of the present disclosure, a system for in-situ continuous monitoring of distributed temperature of a molten medium in a vessel is disclosed. The system comprises a sensor mounting clamp unit fitted at an end of the vessel and at least one waveguide sensor unit fitted to the sensor mounting clamp unit. The sensor mounting clamp unit comprises a horizontal support pipe fitted at a ceiling of the vessel using a ceiling mount extending to an external side along a door of the vessel, an internal slider unit vertically positioned and fitted at a first end of the horizontal support pipe inside the vessel, an external slider unit vertically positioned outside the vessel and fitted at a second end of the horizontal support pipe, and a depth adjuster fitted at a ceiling of the vessel at one end and comprising a holder at the other end supporting the tip portion of the waveguide. The waveguide sensor unit comprises a sensor head positioned outside to the vessel and a waveguide comprising a tip portion attached to the sensor head and immersed in the molten medium at a depth. The waveguide sensor unit is fitted to the internal slider unit via a first clamp and fitted to the external slider unit via a second clamp and configured to slide along a vertical axis through the internal slider unit and the external slider unit, and the depth adjuster is adjusted to change the depth of waveguide in the molten medium for in-situ temperature measurements.

BRIEF DESCRIPTION OF THE DRAWINGS
[0008] Figure 1 illustrates a system (100) for continuous in-situ measurement of distributed temperature of a molten mediums inside a melting furnace in accordance with an exemplary embodiment of the present disclosure.
[0009] Figure 2A illustrates the depth adjuster (18) of the system (100) in accordance with the present disclosure.
[0010] Figure 2B illustrates a side view of the system (100) with the depth adjuster (18) and an adjusting tool in accordance with the present disclosure.
[0011] Figure 3 illustrates the electronic unit connected with the waveguide sensor unit (20) in accordance with the present disclosure.
[0012] Figure 4 illustrates a temperature measuring zone of the waveguide sensor unit (20) in accordance with one example of the present disclosure.
[0013] Figure 5 illustrates a system with a plurality of waveguide sensor units used for in-situ measurement of distributed temperature of a molten metal inside a melting furnace in accordance with another embodiment of the present disclosure.
[0014] Figure 6 illustrates various configurations of waveguide sensor units used for in-situ measurement of distributed temperature of a molten metal in accordance with another embodiment of the present disclosure.
[0015] Figure 7 shows the result of continuous temperature measurement in molten cryolite in accordance with an experimentation of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION
[0016] A system for in-situ continuous measurement of distributed temperature of a molten medium in a vessel (melting furnace) is disclosed. The present inventio discloses a temperature measurement of molten metals, ores and Reactive molten salts based on the ultrasonic guided wave technique. The present invention provides a real time continuous measurement values helping industries to make critical decisions and control damage. The temperature measurement in the present invention is based on the change in ultrasonic wave’s velocity in a waveguide when the waveguide is exposed to molten metal. One or more sensing probes are attached to give continuous real-time molten metal temperature. A mechanical retractable system is used in the present invention, that enables the sensor to move in multiple degrees of freedom to adjust the immersion point and depth.

[0017] In an embodiment of the present disclosure, a system for in-situ continuous monitoring of distributed temperature of a molten medium in a vessel is disclosed. The system comprises a sensor mounting clamp unit fitted at an end of the vessel and at least one waveguide sensor unit fitted to the sensor mounting clamp unit. The sensor mounting clamp unit comprises a horizontal support pipe fitted at a ceiling of the vessel using a ceiling mount extending to an external side along a door of the vessel, an internal slider unit vertically positioned and fitted at a first end of the horizontal support pipe inside the vessel, an external slider unit vertically positioned outside the vessel and fitted at a second end of the horizontal support pipe, and a depth adjuster fitted at a ceiling of the vessel at one end and comprising a holder at the other end supporting the tip portion of the waveguide.

[0018] The waveguide sensor unit comprises a sensor head positioned outside to the vessel and a waveguide comprising a tip portion attached to the sensor head and immersed in the molten medium at a depth. The waveguide sensor unit is fitted to the internal slider unit via a first clamp and fitted to the external slider unit via a second clamp and configured to slide along a vertical axis through the internal slider unit and the external slider unit, and the depth adjuster is adjusted to change the depth of waveguide in the molten medium for in-situ temperature measurements.

[0019] In an embodiment of the present disclosure, the system further comprises an electronic unit communicably connected to the waveguide sensor unit.

[0020] In an embodiment of the present disclosure, the vessel comprises a melting furnace.

[0021] In an embodiment of the present disclosure, the depth adjuster comprises a rack and pinion drive rotated to make a linear movement of the waveguide immersed in the molten medium along the vertical axis through the internal slider unit and the external slider unit, to adsjust the depth of waveguide in the molten medium. The rotation of the rack and pinion drive is controlled either by manually using an adjusting tool from outside or by using an embedded motor coupled with the rack and pinion drive. A controller is communicably connected with the motor for controlling the rotation of the rack and pinion drive.

[0022] In an embodiment of the present disclosure, the molten medium comprises one of molten metal, molten ores and molten salts. The molten metal comprises a metal selected from Aluminium, Zinc, Copper, Silver, Gold, Brass, and bronze. The molten salts comprises cryolite selected from sodium aluminum fluoride (Na3AlF6) and Ammonium chloride(NH4Cl).

[0023] In an embodiment of the present disclosure, the waveguide comprises at least one sheath and a sensor guiding sleeve at the tip portion. The at least one sheath is made of a ceramic material. The at least one sheath and a sensor guiding sleeve is made of a high-density ceramic material selected from a group comprising Silicon Carbide, Boron Nitride, Silicon Nitride, and Aluminium Titanate.

[0024] In an embodiment of the present disclosure, the waveguide is made in a L-shape waveguide configuration.

[0025] In an embodiment of the present disclosure, the tip portion of the waveguide (24) is made in a shape selected from a cylindrical shape, a helical shape, a spiral shape, a J or U shape, and a flat rectangular shape

[0026] In an embodiment of the present disclosure, the system comprises a sleeve made of stainless steel enclosing the waveguide.

[0027] In an embodiment of the present disclosure, the sensor head comprises an ultrasonic transducer, comprising at least one of: a shear wave transducer or a longitudinal wave transducer.

[0028] In an embodiment of the present disclosure, the system comprises a plurality of waveguide sensor units fitted to a plurality of sensor mounting clamp units. The waveguide sensor unit comprises a sensor head positioned outside to the vessel and a cylindrical waveguide attached to the sensor head and immersed in the molten metal at a depth. Thus, the system comprises a plurality of waveguides attached to a plurality of sensor heads.

[0029] Figure 1 illustrates a system (100) for continuous in-situ monitoring of distributed temperature of a molten mediums inside a melting furnace in accordance with an exemplary embodiment of the present disclosure. The molten mediums may comprise molten metals, molten cryolite or molten ore. The system (100) comprises a sensor mounting clamp unit (10) fitted at an end of the melting furnace (200) and a waveguide sensor unit (20) fitted to the sensor mounting clamp unit (10). The sensor mounting clamp unit (10) comprises a horizontal support pipe (12) fitted at a ceiling of the melting furnace (200) using a ceiling mount (15), extending to an outer side of the furnace along a door, an internal slider unit (14) vertically positioned and fitted at a first end of the horizontal support pipe (12) inside the furnace, an external slider unit (16) vertically positioned outside the furnace (200) and fitted at a second end of the horizontal support pipe (12), and a depth adjuster (18) fitted at the ceiling of the furnace at one end and comprising a holder (19) at the other end supporting/holding the waveguide. The external slider unit (16) holds the horizontal support pipe (12) outside the vessel unit and supports the waveguide sensor unit (20) mechanism for precise sensor adjustments. The Ceiling Mount is made of a mild steel fitted at the ceiling to hold the support pipe (12). The depth adjuster (18) is attached to the horizontal support pipe (12) via a top mount at a height, allowing the waveguide to slide and mount at different heights.

[0030] The waveguide sensor unit (20) comprises a sensor head (22) positioned outside to the vessel and a cylindrical waveguide (24) attached to the sensor head and immersed in the molten metal at a depth. The waveguide (24) is fabricated in a ‘L’ shape configuration with a temperature measuring zone, comprises a tip portion (26) immersed in the molten metal. The waveguide (24) comprises a sheath (27) covering the tip portion (26) to prevent the waveguide surface from the high temperature, highly reactive melting environment and a sensor guiding sleeve (28) partially covering the tip portion for a length and leaving the end of the tip portion for temperature measurements. The sheath (27) and the sensor guiding sleeve (28) are made of a ceramic material, preferably made of Silicon Carbide material.

[0031] In an exemplary embodiment of the present disclosure, molten metals comprise metal having a melting point less than 1200℃. Thus, the molten metals may comprise a metal selected from Aluminium, Zinc, Copper, Silver, Gold, Brass, and bronze. Similarly, molten salts may comprise Chlorides, Fluorides, nitrates, and preferably cryolite selected from sodium aluminum fluoride (Na3AlF6) and Ammonium chloride(NH4Cl). The sodium aluminum fluoride has a melting point around 1000℃. Ammonium chloride(NH4Cl) is used in zinc billet manufacturing as a flux to remove oxides from the surface of zinc before it melts and used to form billets. Ammonium chloride(NH4Cl) has a melting point around 350℃.

[0032] In another implementation of the present disclosure, the sheath (27) and the sensor guiding sleeve (28) may be made of a high-density ceramic material selected from a group comprising Boron Nitride, Silicon Nitride, and Aluminium Titanate. The sensor head comprises a shear wave ultrasonic transducer attached with the ‘L’ shape cylindrical waveguide (24). In another implementation of the present invention, the sensor head comprises a Longitudinal wave ultrasonic transducer.

[0033] In another implementation of the present disclosure, the waveguide (24) may comprise two sheath (27) surfaces covering the tip portion (26) to prevent the waveguide surface from highly reactive melting environment.

[0034] Figure 2A illustrates the depth adjuster (18) of the system (100) in accordance with the present disclosure. The depth adjuster (18) comprises a vertical motion drive, which is a rack and pinion drive rotated to make a linear movement of the waveguide (24) immersed in the molten metal along the vertical axis through the internal slider unit (14) and the external slider unit (16), to adjust the depth of waveguide (24) in the molten metal. The rack and pinion drive (18) comprises a rack (1810), a pinion (1820) with a fall proof mechanism (1830) and a waveguide holder (19) at the bottom of the drive (18). The rotation of the rack and pinion drive (18) is controlled using an adjusting tool (1850) from outside thereby adjusting the vertical motion/ depth of waveguide (24) in the molten metal. Figure 2B illustrates a side view of the system (100) with the depth adjuster (18) and an adjusting tool (1850) in accordance with the present disclosure.

[0035] In another embodiment of the present disclosure, the rotation of the rack and pinion drive (18) is controlled by an embedded motor coupled with the rack and pinion drive. The manual tool (1850) may be replaced by a motor connected to the fall proof mechanism via a shaft. The motor may be mounted inside the furnace and a controller is communicably connected with the motor for controlling the rotation and so the rack and pinion drive.

[0036] The system (100) further comprises an electronic unit (30) communicably connected to the waveguide sensor unit (20). The electronic unit supplies electric pulses to the ultrasonic transducer for wave generation in shear mode or a longitudinal mode. Further, the electronic unit receives reflected signals and Time of Reception at the ultrasonic transducer and accordingly process the data (ToR) for determining temperature of molten metal. Figure 3 illustrates the electronic unit connected with the waveguide sensor unit (20) in accordance with the present disclosure.

[0037] In an embodiment, the electronic unit (30) may be mounted on a wall proximal to the melting furnace using an Electrically insulated Buffer plate, and a mild steel enclosure for covering the electronic unit (30).

[0038] A bath of melting furnace comprises a crust having a cylindrical cavity for inserting the waveguide or a probe for temperature measurements into, molten Cryolite maintained at a temperature in a range of 940 ℃ -1000 ℃. The tip portion is inserted into the crust via the cylindrical cavity and immersed into Molten Cryolite of the melting furnace at a depth for measuring temperature of the Molten Cryolite.

[0039] Figure 4 illustrates a temperature measuring zone of the waveguide sensor unit (20) in accordance with one example of the present disclosure. In one example as shown in Figure 4, the tip portion of the waveguide is immersed at a depth of 300 mm from the crust for measuring the temperature of Molten Cryolite.

[0040] Figure 5 illustrates a system with a plurality of waveguide sensor units used for in-situ measurement of distributed temperature of a molten metal inside a melting furnace in accordance with another embodiment of the present disclosure. The system comprises four waveguide sensor units (20a, 20b, 20c, 20d), each waveguide sensor unit comprises a sensor head positioned outside to the vessel and a waveguide attached to the sensor head and immersed in the molten metal at a depth. As shown in Figure 5, four waveguide sensor units (20a, 20b, 20c, 20d) comprises three cylindrical waveguides (24a, 24b, 24c) and a waveguide with a tip portion being flat section (24d). Thus, the system comprises four waveguides (24a, 24b, 24c, 24d) attached to four sensor heads (22a, 22b, 22c, 22d) as shown in Figure 5.

[0041] In an exemplary embodiment, three cylindrical waveguides (24a, 24b, 24d) are fixed on three shear transducers (22a, 22b, 22d) and one waveguide (24c) is fixed on one longitudinal transducer (22c) for producing different modes of waves in the waveguide for temperature measurements as shown in Figure 5. Four cylindrical waveguides (24a, 24b, 24c, 24d) are fabricated with multiple notches of different configurations at the other end.

[0042] In an embodiment of the present disclosure, a plurality of waveguides immersed at different depths in the Molten Cryolite.

[0043] In another embodiment of the present disclosure, each of plurality of waveguides may comprise different types of reflectors, not limited to Notches, Holes, Flat sections for temperature measurement. The purpose of using plurality of waveguides is to obtain more special resolution and verify the redundancy in the temperature measured.

[0044] Figure 6 illustrates various configurations/types of waveguide sensor units used for in-situ measurement of distributed temperature of a molten metal in accordance with another embodiment of the present disclosure. The four waveguides (24a, 24b, 24c, 24d) attached to four sensor heads (22a, 22b, 22c, 22d) as shown in Figure 6. Three waveguides (24a, 24b, 24d) are fixed on three shear transducers (22a, 22b, 22d) and one waveguide (24c) fixed on one longitudinal transducer (22c) for producing different modes of waves in the waveguide for temperature measurements as shown in Figure 6. The four waveguides (24a, 24b, 24c, 24d), each have a tip portion made in various shapes comprising a helical shape (24a), a ‘J’ shape / ‘U’ shape, a helical with a cylindrical (24c) and a flat rectangular (24d). The shape may be chosen based on the requirement or a type of application.

[0045] In another embodiment of the present disclosure, a plurality of waveguides fitted in the melting furnace with a distance between each other. The distance between the waveguides may be equal or different.

[0046] In another embodiment of the present disclosure, the waveguide fitted close to the door immersed at a deeper depth than the waveguides fitted at other locations.

[0047] The waveguide is fabricated in L shape to integrate with the temperature measuring zone. The rack and pinion drive, a specially designed the depth adjusting mechanism, is used for placing the sensor to varying depths. The waveguide has a ceramic sleeve at the measurement zone for protecting the sensor from sudden shock in the crust. Four sensor probes are immersed in molten metal using the depth adjuster. The electronic unit sends the electric pulse to the transducer and multiple wave modes are generated in waveguides. The vibration due to wave modes passes through waveguides and reflected signals are received by same transducer.

[0048] Due to notches in waveguides, reflected signals are received from the notches at different intervals of time. The time of reception of the signal is used to find the temperature of the molten metal. For different temperatures of molten metal, the signal reception time is different. The time of reception (ToR) is correlated to the calibration of thermocouple and an equation is made.

Ax3+Bx2+Cx+D=T(x)
Where x is the TOR. A, B, C , D are constants obtained during the lab calibration trail. For the calibration, the sensor is kept inside the furnace and heating the furnace for various ramping and soaking cycles. During the whole calibration trial, the TOR at various temperatures are noted and the above 3rd order equation between TOR and Temperature was obtained. T(x) is the Temperature corresponding to x. This equation gives the temperature of molten salt for each immersion.

[0049] A setup was made for experimentation and installed in a melting furnace and experimented to validate the continuous measurement and performance of the system. The clamp setup for the sensor installation, comprising an internal and external support and slider unit was made for improving the stability of integrated sensors in molten metal environments. Inside the melting furnace, a robust internal clamp, typically made of mild steel or stainless steel, was aligned with a vertical bracket and securely fastened with bolts. The horizontal support pipe passes through the internal clamp, provides a rigid structure to hold the sensor assembly. The external support clamp, mounted outside the furnace near the door, is attached to the furnace shell using C-shaped clamps and bolts. The external clamp supports the horizontal pipe and has a slider mechanism for precise sensor adjustments. The sensor is positioned with precision using a rack and pinion mechanism, allowing for careful depth adjustments to ensure accurate measurement. The vertical slider allows the sensor to be positioned accurately, and once the desired depth is achieved, the assembly is locked in place to ensure stable and reliable operation. The installation is finalized by making any necessary adjustments for stability, and accommodating the sensor head as required.

[0050] The setup comprises of ultrasonic transducers including Shear transducers and Longitudinal transducers, L shape cylindrical waveguides of 1600mm length and 8mm diameter holders to hold transducer and waveguide setup in position. The clamp setup enables multi-Degree of freedom custom stand assembly for sensor Positioning.

EXPERIMENTAL RESULTS:
[0051] Figure 6 shows the result of continuous temperature measurement in molten cryolite (Na3AlF6) in accordance with an experimentation of the present disclosure. Figure 6 shows continuous temperature measurement in molten cryolite conducted for 20Hrs. A temperature comparison is conducted between waveguide sensor temperature and immersion type K type tip thermocouple. The k type thermocouple was inserted into the ongoing molten bath containing preinstalled with waveguide sensor. The Y axis of Figure 6 shows the molten metal bath temperature and X- Axis shows the time. On verifying the temperature, both the waveguide sensor and thermocouple readings are very close. The temperature recorded by thermocouple matches with the temperature recorded by waveguide sensor and after some time the thermocouple fails to show the correct temperature. A similar trend was observed in multiple trials. It is evident from the trials that the approximate life of the thermocouple inside the molten Cryolite is less than 30 mins.
[0052] Since the waveguide sensor technique is a contact type measurement, it is not affected by the fumes, flame and slag on the surface. Real-time Continuous temperature monitoring in highly reactive molten metals and chemicals is possible with the present invention. Even though the waveguide is an immersion sensor, it can still survive a long time compared to the existing methodologies. The integrated multiple sensors on a single waveguide enable the temperature measurement at various depths. The special sensor positioning mechanisms can reduce manual interventions.
[0053] Real-time monitoring of molten metal/salt/minerals temperature is crucial for optimal casting conditions, homogenization, and alloying. However, until now, there hasn’t been a reliable solution invented for continuous temperature measurement in melting furnaces. Rapid decrease in molten temperature can delay cycle time while overheating can lead to increased energy consumption and furnace refractory damage.
[0054] Continuous temperature monitoring in furnaces and baths provides numerous advantages. It allows for accurate control of alloying reactions, improving refining times and boosting production efficiency. By preventing overheating and minimizing refractory wear, the proposed approach enhances energy efficiency and prolongs the lifespan of equipment. Additionally, it ensures that the furnace is always ready, reducing downtime and increasing productivity. Incorporating process data or spectrum diagnostics can further account for variations in operating conditions. With continuous monitoring, producers gain better control over their processes, leading to improved product quality and operational efficiency.
, C , Claims:We Claim:

1. A system (100) for continuous in-situ monitoring of distributed temperature of a molten medium in a vessel, comprising:
a sensor mounting clamp unit (10) fitted at an end of the vessel (200), wherein the sensor mounting clamp unit (10) comprises:
a horizontal support pipe (12) fitted at a ceiling of the vessel using a ceiling mount (15), extending to an external side along a door of the vessel;
an internal slider unit (14) vertically positioned and fitted at a first end of the horizontal support pipe (12) inside the vessel;
an external slider unit (16) vertically positioned outside the vessel and fitted at a second end of the horizontal support pipe (12); and
a depth adjuster (18) fitted at a ceiling of the vessel at one end and comprising a holder (19) at the other end supporting the tip portion of the waveguide;
at least one waveguide sensor unit (20) fitted to the sensor mounting clamp unit (10), wherein the waveguide sensor unit (20) comprises:
a sensor head (22) positioned outside to the vessel and
a waveguide (24) comprising a tip portion (26) attached to the sensor head and immersed in the molten medium at a depth;
wherein the waveguide sensor unit (20) is fitted to the internal slider unit (14) via a first clamp and fitted to the external slider unit via a second clamp and configured to slide along a vertical axis through the internal slider unit and the external slider unit (16), and the depth adjuster (18) is adjusted to change the depth of waveguide in the molten medium for in-situ temperature measurements.

2. The system as claimed in claim 1, wherein the system further comprises an electronic unit (30) communicably connected to the waveguide sensor unit (20).
3. The system as claimed in claim 1, wherein the vessel comprises a melting furnace.
4. The system as claimed in claim 1, wherein the depth adjuster comprises a rack and pinion drive (18) rotated to make a linear movement of the waveguide (24) immersed in the molten medium along the vertical axis through the internal slider unit and the external slider unit, to adjust the depth of waveguide in the molten medium.
5. The system as claimed in claim 4, wherein the rack and pinion drive (18) comprises a rack (1810), a pinion (1820) with a fall proof mechanism (1830).
6. The system as claimed in claim 4, wherein the rotation of the rack and pinion drive is controlled either by manually using an adjusting tool (1850) from outside or by using an embedded motor coupled with the rack and pinion drive.
7. The system as claimed in claim 6, wherein a controller is communicably connected with the motor for controlling the rotation of the rack and pinion drive.
8. The system as claimed in claim 1, wherein the molten medium comprises one of molten metal, molten ores and molten salts.
9. The system as claimed in claim 8, wherein the molten metal comprises a metal selected from Aluminium, Zinc, Copper, Silver, Gold, Brass, and bronze.
10. The system as claimed in claim 8, wherein the molten salts comprises cryolite selected from sodium aluminum fluoride (Na3AlF6) and Ammonium chloride(NH4Cl).
11. The system as claimed in claim 1, wherein the waveguide (24) comprises at least one sheath (27) and a sensor guiding sleeve (28) at the tip portion (26).
12. The system as claimed in claim 1, wherein the at least one sheath (27) is made of a ceramic material.
13. The system as claimed in claim 1, wherein the at least one sheath (27) and a sensor guiding sleeve (28) is made of a material selected from a group comprising Silicon Carbide, Boron Nitride, Silicon Nitride, and Aluminium Titanate.
14. The system as claimed in claim 1, wherein the waveguide (24) is made in a L-shape configuration.
15. The system as claimed in claim 1, wherein the tip portion (26) of the waveguide (24) is made in a shape selected from a cylindrical shape, a helical shape, a spiral shape, a J or U shape, and a flat rectangular shape.
16. The system as claimed in claim 1, wherein the system comprises a sleeve (25) made of stainless steel enclosing the waveguide (24).
17. The system as claimed in claim 1, wherein the sensor head comprises an ultrasonic transducer, comprising at least one of: a shear wave transducer or a longitudinal wave transducer.
18. The system as claimed in claim 1, wherein the system comprises a plurality of waveguide sensor units (20a, 20b, 20c, 20d) fitted to a plurality of sensor mounting clamp units (10a, 10b, 10c, 10d).